FIG. 1 shows two different collision impact scenarios that may occur to the side 10 of a vehicle in which an occupant 40 may be sitting on a seat 50. FIG. 1A depicts a pole event in which the side 10 of the vehicle may impact a pole 20. The vehicle may impact the pole at a high speed and the pole may be directly aligned with the occupant. As denoted by the dashed lines, the pole 20′ may deform the side 10′ of the vehicle during the impact. The deformation of the vehicle side 10′ results in a localized intrusion into a vehicle cabin 30.
By contrast, FIG. 1B depicts a vehicle-to-vehicle type event in which the side 10 of the vehicle may impact another vehicle 60. As denoted by the dashed lines, the other vehicle 60 may deform the side 10″ of the vehicle during the impact. The deformation of the vehicle side 10″ results in an intrusion into the vehicle cabin 30, which is spread over a wider area than the intrusion with the pole event.
As shown in FIG. 2, such intrusions into the vehicle cabin 30 may be mitigated against by a Side Air Bag (SAB) 60. The SAB 60 may be provided in the seat 50 and may be inflated by an inflator 70 when an impact has been detected. However, with a conventional SAB it is difficult to balance the performance requirements for all side impact events. For example, the pole event will require very fast deployment of the SAB between the occupant and the intruding pole and/or vehicle structure. A suitably high and rapid internal bag pressure is desirable to distribute the load across the occupant torso and avoid the intruding structure pressing through the bag and locally point loading the occupant.
By contrast, in the case of a vehicle impacting the side of the vehicle, although the impact speed may be similar the intrusion rate and load profile will be different. As a result, a vehicle-to-vehicle impact may require the working bag pressure later in the collision event.
However, if the SAB is optimized for the pole event the bag may be under pressure for the vehicle impact, as the SAB may have reached its peak pressure and started to deflate. Conversely, if the SAB is optimized for the vehicle impact the bag may be under pressurized for the pole event.